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2 Sunken Japanese Subs Are Found Off Hawaii

The I-14 is one of 5 Japanese submarines sunk by the U.S. Navy in 1946. Credit
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Researchers on Thursday announced the discovery of two World War II Japanese submarines, including one meant to carry aircraft for attacks on American cities and the Panama Canal, in deep water off Hawaii, where they were sunk 63 years ago.

The submarines, among five that were captured by American forces at the end of the war and taken to Pearl Harbor for study, were found off Oahu at a depth of about 2,600 feet using submersibles from the Hawaii Undersea Research Laboratory, which is financed by the National Oceanic and Atmospheric Administration and located at the University of Hawaii at Manoa. The five were towed to sea in 1946 and torpedoed, and the researchers said one probable reason for that was to avoid having to share any of the technology with the Russian military.

One of the Japanese craft, the I-201, was capable of speeds of about 20 knots while submerged, making it among the fastest diesel submarines ever made. Like other Japanese subs, it had a rubberized coating on the hull, an innovation intended to make it less apparent to sonar or radar.

The other, the I-14, was much larger and slower and designed to carry two small planes, Aichi M6A Seirans. The aircraft, which had folding wings and tails and could carry a torpedo or 1,800-pound bomb, were housed in watertight hangars inside the submarine. They could be brought onto the deck and launched by a catapult. (The only existing Seiran is in the hands of the Smithsonian.)

Together with the discovery four years ago of the I-401, one of two Japanese vessels that were the largest nonnuclear submarines ever built, the finding “really gives us a cross section of some of the great late-war technology” Japan possessed, said Hans K. van Tilburg, of the national marine sanctuaries program at NOAA.

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Terry Kerby, the laboratory’s operations director and chief pilot, said his group had been searching for wrecks from the World War II era since 1992 during “test and trial” dives, in which crews check out the submersibles’ systems before undertaking major scientific explorations. “The big ‘I’ boats have been high on our list,” Mr. Kerby said at a telephone news conference announcing the latest finds.

Mr. Kerby said the discovery of the I-401 helped lead the researchers to the I-14. When the I-401 was announced, retired Navy personnel contacted the laboratory to describe what happened to some of the other subs. One sailor provided 16-millimeter footage he had taken of the I-14 being torpedoed. While shooting the event, he panned the camera to show Diamond Head and other features on the coast.

“We were able to pick some landmarks and triangulate and get a rough position of where the I-14 went down,” Mr. Kerby said.

The submarines were meant to threaten the United States directly, but none of the attacks occurred. The subs were developed too late in the war, and American intelligence was too good. Carl Boyd, a former history professor at Old Dominion University and co-author of “The Japanese Submarine Force and World War II,” said the Navy always knew what the subs were doing.

Mr. Boyd, who was not involved in the discoveries, said that keeping the technology out of Russian hands was only one likely reason for sinking the subs in 1946. Another was the condition of the vessels: they were filthy — they had been crawling with rats when captured — and generally unreliable. “We gained as much as we could out of them,” he said. “The things just weren’t safe.”

A version of this article appears in print on November 13, 2009, on Page A17 of the New York edition with the headline: 2 Sunken Japanese Subs Are Found Off Hawaii. Order Reprints|Today's Paper|Subscribe